FirebaseDatabase Framework Reference

Classes

A FIRDataSnapshot contains data from a Firebase Database location. Any time you read
Firebase data, you receive the data as a FIRDataSnapshot.

FIRDataSnapshots are passed to the blocks you attach with observeEventType:withBlock: or observeSingleEvent:withBlock:.
They are efficiently-generated immutable copies of the data at a Firebase Database location.
They can’t be modified and will never change. To modify data at a location,
use a FIRDatabaseReference (e.g. with setValue:).

Declaration

A FIRDatabaseQuery instance represents a query over the data at a particular location.

You create one by calling one of the query methods (queryOrderedByChild:, queryStartingAtValue:, etc.)
on a FIRDatabaseReference. The query methods can be chained to further specify the data you are interested in
observing

Declaration

A FIRDatabaseReference represents a particular location in your Firebase Database
and can be used for reading or writing data to that Firebase Database location.

This class is the starting point for all Firebase Database operations. After you’ve
obtained your first FIRDatabaseReference via [FIRDatabase reference], you can use it
to read data (ie. observeEventType:withBlock:), write data (ie. setValue:), and to
create new FIRDatabaseReferences (ie. child:).

Declaration

A FIRMutableData instance is populated with data from a Firebase Database location.
When you are using runTransactionBlock:, you will be given an instance containing the current
data at that location. Your block will be responsible for updating that instance to the data
you wish to save at that location, and then returning using [FIRTransactionResult successWithValue:].

To modify the data, set its value property to any of the native types support by Firebase Database:

NSNumber (includes BOOL)

NSDictionary

NSArray

NSString

nil / NSNull to remove the data

Note that changes made to a child FIRMutableData instance will be visible to the parent.